The Empire of Tamriel is on the edge. The High King of Skyrim has been murdered.
Alliances form as claims to the throne are made. In the midst of this conflict, a far more dangerous, ancient evil is awakened. Dragons, long lost to the passages of the Elder Scrolls, have returned to Tamriel.
The future of Skyrim, even the Empire itself, hangs in the balance as they wait for the prophesized Dragonborn to come; a hero born with the power of The Voice, and the only one who can stand amongst the dragons.
Source: The Elder Scrolls Official Site, "The Elder Scrolls V: Skyrim"
Skyrim is a fantasy role-playing game by Bethesda Game Studios and published by Bethesda Softworks. Skyrim is the fifth installment in The Elder Scrolls series, and is a sequel to The Elder Scrolls IV: Oblivion.
The game takes place in the Nordic land of Skyrim, on the fictional continent of Tamriel, about 200 years after the events of Oblivion. At the time of the game, the King of Skyrim has died, provoking civil war amongst the native Nord race. The war is the last in a sequence of events (depicted in each of the previous games in the series) that fulfill a prophecy foretold by the Elder Scrolls; the Nordic god Alduin arises to destroy the world.
Skyrim uses a new, internally developed engine, rather than the Gamebryo engine used for the previous two installments in the series.
Bethesda made their official announcement confirming the game and launch date on Dec. 13, 2010
Source: Wikipedia, "The Elder Scrolls V: Skyrim", available under the CC-BY-SA License.